Safety mechanisms for firearms provide an effective means for rendering a firearm incapable of discharging a round when force is applied directly to the firearm's trigger, for example, by the shooter. However, situations arise when a round may be inadvertently discharged even when the safety mechanism is engaged. For example, when a firearm such as a rifle or pistol is dropped, the trigger mechanism is subjected to inertial forces occasioned by rapid deceleration on impact. The sudden jolt may overcome the safety mechanism and cause the firearm to discharge if a round is chambered. There is clearly an opportunity to improve the dependability of firearm safety mechanisms by augmenting their resistance to inadvertent discharge when subject to inertial forces.